The preferred embodiment is comprised of a process, a computer and a computer program for processing document data containing color data.
The preferred embodiment is concerned particularly with the processing of such document data for optimal output with printing systems.
With the sending of document data to printing systems, the problem of colors being reproduced differently by printing systems still occurs frequently, although in the meantime standardized color systems have been developed, and conversion algorithms have been established between the color profiles. The variety and complexity in the production of document file streams that contain color data as well as with the processing and finally sending to an output device, still leaves however, several unresolved difficulties.
A further problem with the processing of document file streams containing color data is that the color processing is relatively complex and computing intensive. In particular, with the outputting of very large print files from data bases of large computers, having for example several thousand to a hundred thousand individual pages, conversions in the relevant processing steps, for example in a halftone process, may result in significant time-lags. These can be so large that, for example, a subsequent digital high performance printer must be stopped until the preprocessing of the data is complete. Downtimes of this type may result in production losses and printed documents, as well as in additional expenditure required to re-start the device. As a result, it is of some concern that the processing of document data of this type be optimized in this respect, in order that the printing procedure processing steps may be carried out as quickly as possible.
For the above mentioned purposes so-called preflight processes have been developed, whereby the print data has already been checked in an earlier phase with a limited number of checking criteria, in order that any problems may be noted early on. Problems of this type may be, for example, that the color data is in a color profile which is unsuited to the subsequent processing steps, for example, a color profile which is not supported by the subsequent processing steps, or can only be processed in a manner which is relatively slow. Another problem may be that the relative color profile can only be outputted by the output device more slowly.
A further function of preflight processing is to check for consistency in the input data and to, for example, determine inconsistencies which occur as a result of the data being generated by several computer programs, which in the end results in unnecessarily large file sizes or contradictions.
A preflight process contained in U.S. Pat. No. 7,298,516 is known.
A group of data streams have been established in high performance digital printing, whereby large quantities of print data may be very efficiently processed. A series of data streams are specified under the term Advanced Function Presentation (AFP) which are optimized for the transference between various processing steps, e.g. the format Mixed Object Document Content Architecture (MO: DCA) for the transference between computer systems, and the format Intelligent Printer Data Stream (IPDS) for the transference between a host computer or a print server to a printer.
A process is known from US 2004/0036902 A1 in which the AFP data can be analyzed, whereby various data groups may be extracted, or rather, created from the relevant objects in the data stream, such as index data, resource data and document data.
A process is known from WO 01/78375 A1 with which AFP resources concerning color data can be processed. In this process, so-called color conversion tables, in particular, are processed by a computer program.
A process and a system is known of from DE 10 2006 002 886 A1 whereby the color data of an AFP data stream are identifiable. With this, the respective references for numerous color profiles may be obtained, such as so-called full color profiles, like the color profile CMYK (Cyan, Magenta, Yellow, Key), the color profile LAB (Luminance, color axis A from green to red and color axis B from blue to yellow), the color profile RGB (Red, Green, Blue). The references may also refer to other color profiles, such as the color profile HLC (Highlight Color, which means an individual color profile with given colors) or the color profile OCA (Object Content Architecture), which, for example, is defined in the AFP specification Mixed Object Document Content Architecture Reference, 8th edition (May, 2006), published by the International Business Machines Corp. listed under the no. SC31-6802-07, on pages 515-516.
The above named publications are hereby incorporated by reference in the present description as references.